HISTORY OF CRUSTACEA. 



CHAP. IX. 



Fig. 59. w 



attachment closed tubes, ramified like roots, sink 

 into the interior of the host, twisting round its 

 intestine, or becoming diffused among the sac-like tubes 

 of its liver. The only manifestations of life which 



persist in these non 

 plus ultras in the 

 series of retrogres- 

 sively metamor- 

 phosed Crustacea, 

 are powerful con- 

 tractions of the 

 roots, and an alter- 

 nate expansion and 

 contraction of the 

 body, in consequence of which water flows into the 

 brood-cavity and is again expelled, through a wide 

 orifice. 15 



Out of several Cirripedes, which are anomalous both in 

 structure and development, Cryptophialus minutus must 

 be mentioned here ; Darwin found it in great quantities 

 together in the shell of Concholepas peruviana on the 



la Fig. 59. Young of Peltogaster socialis on the abdomen of a small 

 Hermit Crab ; in one of them the fasciculately ramified roots in the 

 liver of the crab are shown. Animal and roots deep yellow. 



14 Fig. 60. Young Saccullna purpurea with its roots ; the animal 

 purple-red, the roots dark grass-green. Magu. 5 diam. 



15 The roots of Sacculina purpurea (fig. 60) which is parasitic upon 

 a small Hermit Crab, are made use of by two parasitic Isopods, namely 

 a Bopyrus and the before mentioned Cryptoniscus planarioides (fig. 42). 

 These take up their abode beneath the Sacculina and cause it to die 

 away by intercepting the nourishment conveyed by the roots; the 

 roots, however, continue to grow, even without the Sacculina, and 

 frequently attain an extraordinary extension, especially when a Bopyrus 

 obtains its nourishment from them. 



